GA-870A-USB3L (rev. 3.1) DDR3 1600MHz and FX CPU issues

[Phantom9]

Hi

I read the post by absic regarding memory controller limitations in AM3 CPUs and that the CPU would limit memory speeds to 1333MHz to avoid damage to the controller. In the mobo listed above, which is AM3+, I was using an Athlon II X4 640 CPU with Corsair vengeance low profile DDR3 1600MHz without any problems. However, when I swapped out the CPU and installed an FX 4100 CPU, which is supposed to be supported in this mobo with latest BIOS, it didn't allow the memory to run at 1600MHz and kept reporting overclock and multiple boot problems until the speed was set back to 1333MHz. I reprted this to Gigabyte who sent me the QVL for this mobo and the memory is not listed. I came to the conclusion that the 870 chipset on the mobo was incompatible with the FX memory controller. I took the FX out and replaced it with a Phenom II X4 965 and with this CPU was able to reset the memory clock to 1600MHz without any issues. Am I correct in thinking that the FX CPU does not like the 870 chipset and will only work with 900 series? Or is there another issue preventing me using the FX on this mobo with 1600MHz DDR3?

Thanks

[Vezina]

The FX 4100 should run at 1600Mhz.

Are you sure you ve used the same timings and voltages in both cases ?!

Try ganged setting with the FX 4100 see what happens

FX 4100 should be used with the so called 9xx chipsets ,but technically speaking 9xx and 8xx AMD chipsets are the same under the hood.

Maybe the BIOS has a bug.Maybe compatibility issues.

Performance wise there is no huge increase from going to 1600 Mhz on the FX 4100.

I would keep the X4 965 in your place.

If you want more get a FX 6300.

[Phantom9]

Hello Vezina
The FX 4100 supports memory speeds up to 1866MHz. The 870 chipset, although present on the AM3+ mobo, does not appear to work correctly with the FX CPUs, despite the F4 BIOS update. It is designed, I believe, to work with the 900 series chipset. On the other hand, the 800 series chipset is designed to support Athlon and Phenom that's why I had no problems configuring the BIOS to support 1600MHz DDR3 memory with either of these CPUs.

I have decided not to put the FX back on the mobo and agree that the Phenom II is better. It does run a lot hotter than the Athlon II its replaced and I am only using stock heat sink. Much better than the Athlon II X4, though.

Regards